1. General

• Model: JANCD‑SR21‑1 (sometimes written JANCD‑SR21)

• Type: Main CPU / Axis Processor Board (backplane slot)

• Manufacturer: Yaskawa Electric (YASNAC / Motoman)

• Function: System control + 4‑axis servo motion control (position/velocity/torque)

• Compatibility: YASNAC LX, MX series; Motoman ERC robots

• Not compatible: XRC, NX100, DX, YRC controllers

2. Specifications

• Power: +5 V, ±12 V from backplane; typical ~2.0 A

• Processor: High‑speed 16‑bit motion CPU (upgraded from SR20)

• Memory: 512 KB RAM / 256 KB ROM (larger than SR20B)

• Axes: 4 synchronized servo axes (linear/circular interpolation, electronic gear)

• Interfaces: Servo bus, encoder (incremental/absolute), limit/home, emergency stop, system I/O, backplane bus

• Operating temp: 0 °C to 45 °C; storage −20 °C to 60 °C

3. Key Features

• Upgraded performance: Faster DSP, more memory, improved real‑time control vs SR20/SR20B

• 4‑axis closed‑loop motion control with trajectory planning (trapezoidal / S‑curve)

• Integrated PLC: Enhanced sequence/logic handling (M/S/T codes, machine I/O)

• System management: Coordinates with servo boards, I/O boards, operator panels

• Protection: Hardware overcurrent, overvoltage, overheat, watchdog; self‑diagnosis alarms

4. Compatibility & Replacement

• Replaces: JANCD‑SR20, SR20B (drop‑in, better performance)

• Works with:

  • CPU/backplane: JANCD‑SR21 series

  • Servo boards: JANCD‑SP series

  • I/O boards: JANCD‑IO series

  • Operator panels: YASNAC LX/MX panels

5. English Summary